Rotating drum heater for synthetic yarn



Jan. 7, 1969 H. w. MCCARD ETAL 3,420,983 ROTATING DRUM HEATER FORSYNTHETIC YARN Filed Sept. 2l, 1966 Sheet Jan- 7, 1969 H. w. MccARD ETAL3,420,983

ROTATING DRUM HEATER FOR SYNTHETIC YARN Filed Sept. 2l, 1966 Sheet 2of`2 3% Zig. f .(5,53 Kg 7 f A I United States Patent O 4 ClaimsABSTRACT F THE DISCLOSURE A device for continuously heat treatingrunning lengths of heat treatable synthetic yarn, having a housing, ashaft rotatable within the housing, a hollow heat conductive metal drummounted on t-he shaft and adapted to receive a plurality of turns ofyarn fed onto the drum at one end and removed from the other end, thedrum having a series of grooves of c-hanging circumference starting nearthe center and progressively decreasing in diameter toward the take offend of the drum in accordance with change in length in the yarn as it isheated, a heating element mounted to the housing about the shaft withinthe hollow of the drum and a post mounted on the housing forlongitudinally separating the turns of yarn about the drum.

This invention reates to a device for heating running length of yarn andmore particularly to a device for heat treating synthetic continuousfilament yarn.

The invention is concerned with a yarn heating device for -heat treatingsynthetic and especially thermoplastic contin-uous filament yarn, whichmay be employed as an adjunct to any of a wide variety of textiledevices. For example, the yarn heater of the invention may be employedto improve the stability of synthetic yarn, to reduce the residualshrinkage of such yarn, to reduce the residual stretch of such yarn, asan adjunct to false twisting yarn to increase its bulk and stretchcharacteristics as by imparting a permanent S or Z twist to the yarn, orfor other purposes.

In conventional false twisting mechanism for nylon or other yarn, longheating tubes |have been employed containing electrical resistancecoils, air, steam, or other heat exchange fluids. The nylon yarn as wellknown is heated to a temperature approaching its melitng point.

In todays modern process machinery, running speeds of up to 150,000r.p.m. and greater wherein the linear speed is of the order of 40 yards/minute and upward have been reached and this has necessitated usingheating tubes of up to 30 to 45 inches in length so as to provide enoughheating area to reach the required temperatures. Such mechanisms,however, are not only space consuming but often very inefficient inreaching the temperature required to soften the synthetic yarn.

It is therefore an object of this invention to provide a more compactand more efcient yarn heater.

It is a further object of this invention to eliminate the long heatertube in a yarnheater by providing a heater for the yarn wherein the yarnis run circumferentially around a drum heater.

It is a further object of this invention to provide a yarn heater thatis compatible with textile mechanisms at higher speeds of operation.

It is a further object of this invention to internally heat the drum toprovide the source of heat for the yarn.

It is a further object of this invention to provide more accuratetemperature control in the heating of yarns.

It is a further object to avoid damage and to reduce snagging of theyarn during the heating process by r-unning the yarn around a smoothrotatable heated drum.

A further object is to allow for shrinkage or produce stretch of theyarn during heating by tapering the drum inwardly or outwardly towardthe take olf end, or to provide both features.

A further object is to provide a plurality of independent grooves on thedrums surface, wherein the effective diameter at the bottom of thegrooves progressively decreases, or increases, or increases anddecreases, toward the take off end of the drum which allows forshrinkage or provides stretch, or a combination thereof, and also keepsthe turns of yarn longitudinally separated on the drum.

A further object is to provide a Xed guide post adjacent the revolvingdrum heater to keep the turns of yarn longitudinally spaced apart on thesurface of the drum.

A further purpose is to drive the drum by an electric motor of limitedtorque capability, such as a shaded pole induction motor through a conepulley so that precise adjustments of speed can readily be accomplished,but the drive can function notwithstanding that it is not previouslyadjusted at the speed at which the yarn is received from furthermechanism or taken olf by further mechanism.

Further objects will appear from the following description of thedrawings.

FIGURE l is a plan view of the yarn heater of this invention.

FIGURE 2 is a top plan view of the heater of FIG- URE l.

FIGURE 3 is a fragmentary right side view of the heater of the FIGURE l.

FIGURE 4 is an enlarged cross sectional view of the heater taken alongthe lines 44 of FIGURE 3.

FIGURE 5 is an exploded perspective view showing the relationshipbetween the various parts of the heater.

FIGURE 6 is a perspective view of the yarn heater in operation showingthe travel of the yarn around the circumference of the dr-urn.

FIGURE 7 is an axial section of a modied contour for the drum, as usedin the invention.

FIGURE 8 is an axial section showing a further modication of the drumcontour to stretch the yarn after heating.

FIGURE 9 is a view similar to FIGURE 6, showing the drum of FIGURE 8applied in the processing of yarn using a fixed guide post, as shown inFIGURE 6.

FIGURE l0 is an axial section of a modified embodiment of a drumaccording to the invention which first stretches the yarn and thenpermits it to shrink after heating.

FIGURE ll is a view showing the drum of FIGURE 10 in use in cooperationwith a lixed guide post, as in FIGURE 6.

FIGURE 12 is a side elevation partially diagrammatic showing the drivefor the heater of the invention.

With reference to the drawings there is shown a yarn heater consistingof a drum 20 suitably secured as by means of a screw 21 to a hollow axleor shaft 22 rotatably supported within a housing 23 by bearings 24. Thehousing flares outwardly forming a dish shaped depression 25 at one endwherein there is secured a ceramic or other suitable rigid insulatingmaterial plate 26 that extends upwardly forming a cylinder 27 about theaxle 22 of the drum. The plate 26 is bolted to the housing by suitablefastening bolts 28 and also by a xed guide post 34, the function ofwhich will be further described below. The bolts 28 pass through thehousing and into a support element 29 of the textile machinery to securethe heater in its proper location.

Supported by the ceramic plate and adjacent the interior surface of thedrum 20 as shown in FIGURE 4 is a heating element 30 which preferably isan electric resistance coil having electrical leads 30 but mayalternatively be air, steam or any other type of heat exchange uidheater. Alternatively heating coils may be provided with suitableconnections in the interior structure of the drum itself. A vent 31 isprovided in the side of the hollow axle 22 to permit air circulation andconsequent cooling of the bearings 24.

The drum can be made of aluminum or any other good heat conductive metaland should preferably be coated with cermet or any other substance thatwill prevent stain from being imparted to the yarn as it passes over thedrum. The feeding end of the drum is cylindrical having a lip 32 whichprevents the yarn from falling olf the end of the drum.

In some forms of yarn such as nylon allowance should be made forshrinkage in the yarn due to heating as in FIGURES l to 6 inclusive, andthus a plurality of grooves 33 have been provided on the surface of thedrum starting around its mid section and decreasing in diameter towardthe take off end' of the drum. These progressively deeper grooves allowfor shrinkage caused by the heating and/ or twisting of the yarn.Instead of a plurality of grooves a cone shaped drum may be providedwith a large diameter initially tapering smoothly to a smaller one atthe take off end.

In the particular embodiment shown, the irst groove 33' would have adiameter approximately 5% less than the diameter of the cylindricalportion of the drum, the grooves progressively getting deeper until thelast groove 332 had a diameter approximately less than the diameter ofthe drum. However, it will be understood that the decrease in diameterof the grooves may be greater or less 'depending upon the amount ofshrinkage which will occur in the yarn to be processed. While threegrooves have been shown on the drum in the drawing, any number can beused depending on the kamount of shrinkage of the yarn and the size ofthe drum.

In operation of the device as shown in FIGURE 6, the yarn is fed from apackage not shown on the left onto the lower end of the drum 20 and offthe top end of the drum after being properly heated into other textilemechanism not shown which requires that the yarn be heated.

It has been found that it is advantageous to guide the yarn around aguiding element or post 34 having a plurality of grooves 35 runningtransverse to the length of the post. The yarn passes around the fixedguiding post 34 and then takes a turn around the drum and in this waythe post keeps the yarn passes longitudinally separated and additionallyprevents creeping of the yarn. The posts are easily removable and henceinterchangeable for different size yarn making the heater adaptable forvarious sizes without having to change the heater drum itself.Alternatively an idle smaller drum rotatably mounted on the device andcontaining grooves therein may be used in place of the xed guide post tokeep the yarn passes separated.

In an actual example, nylon yarn of 70 denier having 34 filaments andyarn of 70 denier having 17 rilaments were wrapped around a drumrevolving at high speed (spindle speed about 120,000 r.p.m.) and heatedto a temperature from about 350 to 450 F. The device of FIGURES 1 to 6is particularly suitable for polyester yarn. The yarn should be heatedto a temperature approaching its melting point so that it will besuiciently softened to receive a permanent set. The number of passes ofyarn around the drum is determined by the speed of the drum and thelength of time the yarn should be in contact with the drums surface inorder to reach the required temperature.

The drum diameter is not critical and it has been constructed with thesmooth cylindrical portion over part 'of its surface so that the span oftime required for the heating can be adjusted merely by taking off oradding more turns of the yarn to the drum and/or increasing ordecreasing the speed of travel of the yarn. While the initial coldtorque of the heating device is nominal, once the mechanism is atoperating temperatures the drag on the yarn is negligible.

A cover not shown may optionally be placed over the mechanism after ithas been threaded with the yarn having necessary inlet and outlet portsin an effort to conserve the heat and to prevent exposure of the yarn tooutside elements or possible dangers of breakage.

FIGURE 7 is a modification of the drum construction shown in FIGURES 1to 6 provided with relatively sha1- lower, progressively decreasingannular grooves 333 at the take off end, permitting shrinkage of theyarn after heating. This permits 10% shrinkage in four steps.

In some cases it is desirable to actually stretch the yarn rather thanshrinking it. In FIGURES 8 and 9 the annular grooves 334 at the take oifend are progressively larger than the drum and positively stretch theyarn 12% in four steps, as shown. This form is especially useful fornylon where considerable permanent twist is imparted, as in stretchyarn, and it is desirable to obtain a bulking effect.

FIGURES 10 and 11 show a modied form of drum, which at the take oif endhas first an annular groove 335 larger in diameter than the drum whichstretches the yarn and then a succession of annular grooves 336 smallerthan the dum, which permits the yarn to shrink. This is usefulparticularly to produce novelty. yarns that have unusual effects, as forexample for polyester yarns for the piles of carpets and rugs. Thisillustrates the concept of having the bottoms of the grooves changetheir dirnension in one direction and then in another direction towardthe take olf end.

FIGURES 7 to l1 inclusive show a slightly different construction of thedrum at the point where it engages the spindle, and the insultation ofthe heater is appropriately relieved to avoid interference.

The yarn can be pulled around the drum by suitable means in which casethe drum will idle, but in many cases the drum will be driven. Thispresents a problem since the yarn will be received from other mechanismat a speed controlled by such other mechanism and passed on to furthermechanism at a speed controlled by the further mechanism. It is thuspossibile that the speed of the drum lmight be slightly different fromthe speed at which the yarn is either received or taken off. To allowfor this contingency, I prefer to drive by a cone pulley 38 on the rearend of axle or shaft 22 which is engaged by a suitably rubber or plasticrim of driving wheel 40 on shaft 41 of driving motor 42 which isadjustable along a path suggested by the arrows 43, convenientlyproviding adjusting guide-ways and clamping means not shown. The motoris desirably a motor of limited torque so that if it is set at aslightly improper speed with respect to the predetermined travel of theyarn the motor will slightly slip in either direction. A shaded poleinduction motor or a synchronous variation thereof is convenient forthis purpose.

Instead of nylon and polyster, the heating drum is also applicable toother types of synthetic yarns which include but are not limited to thefollowing such as: polyvinyl chloride, polyvinyl chloride acetates,cellulose acetates, polypropytlene and other thermoplastic fibers.

The invention has thus provided a compact and inexpensive heater foryarn that is accurate, efficient and readily adaptable to all sizes andtypes of yarn and machine speeds without additionally adding any risk tothe process such as breaking of the yarn with the consequent failure ofthe operation and the necessary restarting of the process.

In view of our invention and disclosure varations and modifications tomeet individual whim or particular need will doubtless become evident toothers skilled in the art, to obtain all or part of the benefits of ourinvention without copying the apparatus shown, and we therefore claimall such insofar as they fall within the reasonable spirit and scope ofour invention.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent is:

1. In a device for continuously heat treating running lengths of heattreatable synthetic yarn to impart bullk and stretch characteristics, ahousing, a shaft rotatably supported within the housing, a hollow lheatconductive metal drum mounted on the shaft and adapted to receive aplurality of turns of yarn fed onto the drum at one end and removed fromthe other end, said drum having a series of grooves of changingcircumference starting near the center and progressively decreasing indiameter toward the take off end of the drum in accordance with changein length in the yarn as it is heated, a heating element mounted to thehousing about the shaft Within the hollow of the drum and a post mountedon the housing for longitudinally separating the turns of yarn about thedrum.

2. A device of claim 1 wherein the drum is of aluminum.

References Cited UNITED STATES PATENTS 7/ 1940 Coleshill et al.

8/ 1943 Bert-hold.

6/1952 Barker 28-71.3 X 3/1956 Herbert et al. 28-71.3 X l/ 1962 Kleekammet al.

1/ 1963 Fritzemeier et al. 28-71.3 X 7/ 1966 "Michalek,

GEORGE HARRIS, Primary Examiner.

ROY N. ENVALL, JR., Assistant Examiner.

U.S. Cl. X.R.

